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Yesterday after I took some photos, I inserted the SD card (2GB) from my Nikon D80 to my computer. It showed up in Finder as usual, but after I opened the directory, it shows that my .NEF files are all "zero byte". However, it shows that there are 1.17GB of files on the SD card when I check the info of the SD card in Finder. I have tried recovering the files with Wondershare Photo Recovery, but no luck. What is causing this and how do I fix this?